An EL element is characterized in that: holes and electrons injected from facing electrodes are coupled within a light emitting layer thereof; a fluorescent substance in the light emitting layer is excited by the energy generated by the coupling; and the fluorescent substance thus excited emits light of a color in accordance with the type of the fluorescent substance. The EL elements have been attracting attention as self-luminescent display elements each having a plane surface. Among those EL elements, an organic thin film EL display using an organic substance as a luminescent material has high emitting efficiency, that the organic thin film EL display realizes light emission of a high brightness, even when an applied voltage is less than 10 V, and enables light emission with a simple element structure. Thus, the organic thin film EL display is expected to be applied to a low price simple display, such as an advertisement display, which displays a specific pattern by light emission.
When a display using such an EL element as described above is manufactured, patterning of an electrode layer, a light emitting layer, a buffer layer and the like is generally carried out.
When patterning of each layer as described above is carried out, a substrate is subjected to a liquid repellent treatment in advance, in some cases, in order to improve the patterning precision. As a result of such a liquid repellent treatment, for example, color mixture of a light emitting layer comprising a plurality of colors is prevented, whereby a highly precise EL element can be manufactured.
However, by the liquid repellent treatment, unwanted portion may be subjected to the treatment in some cases. FIG. 6 shows such an undesirable state. In FIG. 6, a first electrode layer 62 is formed on a substrate 61, and an insulating layer 63 is formed so as to cover edge portions of the first electrode layer 62. The insulating layer 63 has been subjected to a liquid repellent treatment. Because of the liquid repellent treatment subjected to the insulating layer 63, there may be an inconvenience such as a film thickness of a light emitting layer 64, which is formed thereafter, is thinner, or a small clearance “a” is formed at a boundary between the light emitting layer 64 and the insulating layer 63. Such uneven film thickness and clearance “a” may could cause inconvenience, for example, a short-circuit due to a continuity between a second electrode layer 65 formed on the light emitting layer 64 and the first electrode layer 62. Thus, an inconvenience resulting from the liquid repellent treatment needs to be prevented.